JP3533833B2 - Brake drum structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved brake drum structure.

[0002]

2. Description of the Related Art As a conventional brake drum structure, there is one shown in FIG .

To explain this, the brake drum 10 is formed in a cylindrical shape with a bottom, and has a cylindrical portion 20 with which a brake shoe slides, and a disk portion 30 attached to a rotating shaft. A slide contact surface 21 with which the brake shoe slides is formed on the inner circumference of the cylindrical portion 20. The disk portion 30 has a mounting surface 31 for the rotating shaft, and is fastened to the rotating shaft via a bolt (not shown) inserted through the mounting surface 31.

In the brake drum 10, a vibration mode in which the disk portion 30 is deformed into a film shape is generated at the time of braking in which a brake shoe is slidably contacted, and a vibration mode in which the cylindrical portion 20 is deformed into a corrugated plate shape is generated, and two vibration modes are generated. When the above are coupled to have an unstable eigenvalue, noise called so-called brake squeal may be generated from the brake drum 10.

To cope with this, in Japanese Utility Model Laid-Open No. 75536/1993, as shown in FIG.
It is disclosed that the mounting surface 31 is formed to increase the rigidity of the mounting surface 31.

By increasing the rigidity of the mounting surface 31,
Coupling of the vibration mode of the disc portion 30 with the vibration mode of the cylindrical portion 20 is suppressed, and the squeal of the brake can be prevented.

[0007]

However, in such a conventional brake drum structure, the disk portion 30 is used.
When the rigidity of the mounting surface 31 is increased by forming the stepped portion 33 on the mounting surface 31, when the mounting surface 31 is distorted by the input from the rotating shaft side, the deformation of the cylindrical portion 20 having a relatively low rigidity becomes large, The roundness of the cylindrical portion 20 is reduced, which causes judder and the like.

The present invention has been made in view of the above problems, and it is an object of the present invention to simultaneously prevent the squeal of the brake and the occurrence of judder and the like in the brake drum structure.

[0009]

According to a first aspect of the present invention, there is provided a brake drum structure comprising: a disc portion having a mounting surface connected to a rotation shaft of a wheel; and a cylindrical portion having a sliding contact surface with which a brake shoe slides. In a brake drum structure including a stepped portion formed by bending a disc portion in a crank shape, the corner portion formed by the disc portion and the cylindrical portion has a rectangular cross section.
A meat thief formed to be removed in a ring shape is provided .

The brake drum structure according to claim 2 is
In the invention according to claim 1, the stepped portion is formed in a circular shape concentric with the rotation center.

The brake drum structure according to claim 3 is
In the invention according to claim 1, the stepped portion is formed in a polygonal shape having a plurality of corners.

The brake drum structure according to claim 4 is
In the invention according to claim 1, the stepped portion is formed in a shape having a U-shaped protruding portion.

[0013]

[0014]

In the brake drum structure according to the present invention, a vibration mode in which the brake drum of the brake drum is deformed into a film shape on the disk portion at the time of braking and a cylindrical portion is deformed into a corrugated plate shape is generated. When the two vibration modes are coupled and become an unstable eigenvalue, noise called so-called brake squeal is generated from the brake drum.

By forming the stepped portion in the disc portion to increase the rigidity of the disc portion, it is possible to prevent the vibration mode of the disc portion from coupling with the vibration mode of the cylindrical portion, and to prevent the squeal of the brake. it can.

However, if the rigidity of the mounting surface is increased by forming the stepped portion on the disk portion, if the mounting surface is distorted by the input from the rotating shaft side, the cylindrical portion having relatively low rigidity is deformed. It becomes large and the roundness of the sliding contact surface is reduced, which causes judder and the like.

To cope with this, the present invention deals with this by providing the brake drum with a rectangular cross section at the corners formed by the disk portion and the cylindrical portion.
Since a meat thief part that is designed to be removed in a circular shape is provided , even if the disc part is distorted due to input from the rotating shaft side, the disc part deforms in the vicinity of the meat thief part having relatively low rigidity. The deformation of the cylindrical portion can be suppressed, the circularity of the sliding contact surface can be maintained, and the occurrence of judder or the like can be prevented.

In the brake drum structure according to claim 2, since the stepped portion is formed in a circular shape concentric with the rotation center,
The rigidity of the disc portion can be increased in response to different numbers of vibration modes, and the squeal of the brake can be prevented.

In the brake drum structure according to the third aspect, since the stepped portion is formed in a polygonal shape, the corner portion of the stepped portion is arranged at the antinode of each vibration mode, so that the vibration of the disk portion is generated. The rigidity of the generated portion can be effectively increased, and the squeal of the brake can be prevented.

In the brake drum structure according to the fourth aspect, since the stepped portion is formed by synthesizing the U-shaped protrusion, the U-shaped protrusion is arranged at the antinode of each vibration mode. As a result, the rigidity of the portion of the disk portion where the vibration occurs can be effectively increased, and the squeal of the brake can be prevented.

[0021]

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 10 is a brake drum, which is connected to a rotating shaft (hub) of a wheel (not shown). A brake shoe (not shown) is pressed inside the brake drum 10 to generate a frictional force to brake the vehicle.

The brake drum 10 is formed in a cylindrical shape with a bottom, and has a cylindrical portion 20 with which a brake shoe slides, and a disc portion 30 attached to a rotating shaft. A slide contact surface 21 with which the brake shoe slides is formed on the inner circumference of the cylindrical portion 20.

As shown in FIG. 2, the disk portion 30 has a mounting surface 31 for the rotating shaft, and four bolt holes 32 are opened in the mounting surface 31. The disk portion 30 is fastened to the rotary shaft via bolts (not shown) that pass through the bolt holes 32.

A stepped portion 33 is formed on the disk portion 30,
The rigidity of the mounting surface 31 is increased. Step part 3
No. 3 has a crank-shaped cross section.

In this embodiment, the stepped portion 33 has the mounting surface 31.
Is formed into a cylindrical shape along the outer periphery of the. The stepped portion 33 is formed concentrically with the cylindrical portion 20 and the disc portion 30.

The brake drum 10 is formed with a thin portion 34 between the mounting surface 31 and the cylindrical portion 20 to reduce its cross section.

The meat robber portion 34 is formed so that the corners formed by the disk portion 30 and the cylindrical portion 20 are removed with a rectangular cross section.

In the present embodiment, the meat robber portion 34 has the cylindrical portion 20.
Also, it is formed in an annular shape concentric with the disk portion 30.

With the above construction, the operation will be described below.

As shown in FIG. 3, in the brake drum 10, a vibration mode in which the disk portion 30 is deformed into a film shape at the time of braking in which the brake shoes are in sliding contact, and a vibration mode in which the cylindrical portion 20 is deformed into a corrugated plate shape is generated. When the vibration modes are generated and the two vibration modes are combined to have an unstable eigenvalue, noise called so-called brake squeal is generated from the brake drum 10.

As a measure for preventing the brake squeal, a stepped portion 33 is formed on the disc portion 30 to increase the rigidity of the mounting surface 31. By increasing the rigidity of the mounting surface 31, it is possible to prevent the vibration mode of the disk portion 30 from coupling with the vibration mode of the cylindrical portion 20.

In the present embodiment, since the stepped portion 33 is formed in a circular shape concentric with the center of rotation, the rigidity of the disk portion 30 can be increased corresponding to different number of vibration modes, and the squeal of the brake can be prevented. it can.

However, when the rigidity of the mounting surface 31 is increased by forming the stepped portion 33 on the disk portion 30, when the mounting surface 31 is distorted by the input from the rotating shaft side, the cylinder having relatively low rigidity is formed. The deformation of the part 20 becomes large, and the cylindrical part 2
The roundness of 0 will decrease and cause judder etc.

FIG. 4 shows the results of measuring the circularity of the sliding contact surface in accordance with the flatness of the disc, when the stepped portion is formed on the disc and when the disc is formed in a flat plate shape. It represents. From now on, when the stepped part is formed on the disk part,
It can be seen that the circularity of the sliding contact surface with respect to the flatness of the disk portion is lower than that in the case where the disk portion is formed in a flat plate shape.

In order to cope with this, the present invention forms a thin portion 34 for reducing the cross section between the mounting surface 31 and the cylindrical portion 20, so that the mounting surface 31 is distorted by the input from the rotating shaft side. Even if it occurs, it is possible to suppress the deformation of the cylindrical portion 20 due to the deformation of the disk portion 30 in the vicinity of the meat thief portion 34 having a relatively low rigidity, maintain the roundness of the cylindrical portion 20, and prevent the judder or the like. Can be prevented.

Next, the embodiment shown in FIG. 5 will be described. The parts corresponding to those in FIG. 2 are designated by the same reference numerals.

In this embodiment, the brake drum 10
The stepped portion 35 is formed in a substantially rectangular shape. Stepped portion 35
Each corner portion 36 is formed by being curved in an arc shape.

As shown in FIG. 3 (c), the brake drum 10 has a disk portion 3 at the time of braking when the brake shoes are in sliding contact.
Corresponding to the generation of the four vibration modes of 0-shaped film deformation, the corner portion 36 of the stepped portion 35 is arranged at the antinode of each vibration mode.

The brake drum 10 has a meat-thief portion 34 that reduces the cross section between the mounting surface 31 and the cylindrical portion 20.
Is formed. Also in the present embodiment, the meat robber portion 34 has a rectangular cross section and is formed in an annular shape concentric with the cylindrical portion 20 and the disc portion 30.

With the above construction, the operation will be described below.

By arranging the corner portion 36 of the stepped portion 35 at the antinode portion of each vibration mode, the rigidity of the portion of the disk portion 30 where the vibration is generated is effectively increased, and the squeal of the brake is generated. Can be prevented.

Next, the embodiment shown in FIG. 6 will be described. The parts corresponding to those in FIG. 2 are designated by the same reference numerals.

In this embodiment, the brake drum 10
The stepped portion 37 is formed along the outer shape of the dozen. The stepped portion 37 has four U-shaped protrusions 38.

As shown in FIG. 3 (c), the brake drum 10 has a disk portion 3 at the time of braking when the brake shoes are in sliding contact.
Corresponding to the occurrence of four vibration modes in which the film shape is deformed to 0, the protruding portion 38 of the stepped portion 37 is arranged at the antinode portion of each vibration mode.

The brake drum 10 has a meat-thief portion 34 for reducing the cross section between the mounting surface 31 and the cylindrical portion 20.
Is formed. Also in the present embodiment, the meat robber portion 34 has a rectangular cross section and is formed in an annular shape concentric with the cylindrical portion 20 and the disc portion 30.

With the above construction, the operation will be described.

By arranging the U-shaped projecting portion 38 at the antinode of each vibration mode, the rigidity of the portion of the disk portion 30 where the vibration is generated is effectively increased, and the squeal of the brake is generated. Can be prevented.

Next, the embodiment shown in FIG. 7 will be described. The parts corresponding to those in FIG. 2 are designated by the same reference numerals.

In the present embodiment, the brake drum 10
The stepped portion 39 is formed along the outer shape of the dozen. The stepped portion 39 has six U-shaped protrusions 40.

As shown in FIG. 3 (a), the brake drum 10 has a disk portion 3 during braking when the brake shoes are in sliding contact.
Corresponding to the occurrence of the six vibration modes of 0-shaped film deformation, the protrusion 40 of the stepped portion 39 is arranged at the antinode of each vibration mode.

The brake drum 10 has a meat-thief portion 34 for reducing the cross section between the mounting surface 31 and the cylindrical portion 20.
Is formed. Also in the present embodiment, the meat robber portion 34 has a rectangular cross section and is formed in an annular shape concentric with the cylindrical portion 20 and the disc portion 30.

With the above construction, the operation will be described below.

By disposing the projecting portion 40 of the stepped portion 39 in the antinode portion of each vibration mode, the rigidity of the portion of the disk portion 30 where the vibration is generated can be effectively increased, and the squeal of the brake is generated. Can be prevented.

[0056]

[0057]

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

As described above, according to the brake drum structure of the first aspect of the invention, the vibration mode of the disc portion is changed to the cylindrical portion by increasing the rigidity of the disc portion by forming the stepped portion on the disc portion. It is suppressed from coupling with the vibration mode of and the squeal of the brake is prevented. And the brake drum is a disc
The corners formed by the circular and cylindrical parts are circularly cut with a rectangular cross section.
A meat thief portion formed so as to be removed is provided to suppress deformation of the cylindrical portion due to input from the rotating shaft side, maintain circularity of the cylindrical portion, and prevent judder and the like from occurring.

According to the brake drum structure of the second aspect, since the stepped portion is formed in a circular shape concentric with the rotation center,
The rigidity of the disc portion can be increased in response to different numbers of vibration modes, and the squeal of the brake can be prevented.

According to the brake drum structure of the third aspect, since the stepped portion is formed in a polygonal shape, the corner portion of the stepped portion is arranged at the antinode of each vibration mode, so that the disk portion It is possible to effectively increase the rigidity of the portion where vibration occurs and prevent the squeal of the brake from occurring.

According to the brake drum structure of the fourth aspect, since the stepped portion is formed by synthesizing the U-shaped protrusion, the U-shaped protrusion is formed on the antinode of each vibration mode. By being arranged, the rigidity of the portion of the disk portion where the vibration occurs can be effectively increased, and the squeal of the brake can be prevented.

[0084]

[Brief description of drawings]

FIG. 1 is a sectional view of a brake drum showing an embodiment of the present invention.

FIG. 2 is a side view of the brake drum.

FIG. 3 is a diagram showing a vibration mode generated in a brake drum.

FIG. 4 is a characteristic diagram showing the relationship between the flatness of a disk portion and the circularity of a sliding contact surface.

FIG. 5 is a side view of a brake drum showing another embodiment.

FIG. 6 is a side view of a brake drum showing still another embodiment.

FIG. 7 is a side view of a brake drum showing still another embodiment.

FIG. 8 is a sectional view of a brake drum showing a conventional example.

FIG. 9 is a sectional view of a brake drum showing a conventional example.

[Explanation of symbols]

10 brake drum 20 Cylindrical part 21 Sliding surface 30 disk 31 Bonding surface 33 Stepped part 34 Meat theft 35 Stepped part 36 corners 37 Stepped part 38 corners 39 Stepped part 40 corners

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-200826 (JP, A) JP-A-60-4635 (JP, A) Actual opening 61-23539 (JP, U) Actual opening Sho-58- 22535 (JP, U) Actual Development Sho 61-146633 (JP, U) Japanese Patent Sho 45-3849 (JP, B1) Actual Public Sho 46-33468 (JP, Y1) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16D 49/00-71/04

Claims (4)

(57) [Claims] 1. A disk portion having a mounting surface connected to a rotating shaft of a wheel, a cylindrical portion having a sliding contact surface with which a brake shoe slides, and a step formed by bending a cross section of the disk portion into a crank shape. In the brake drum structure including the attachment portion, the corner portion formed by the disc portion and the cylindrical portion has a rectangular cross section.
A brake drum structure characterized by having a meat robber formed to be removed in an annular shape . 2. The brake drum structure according to claim 1, wherein the stepped portion is formed in a circular shape concentric with the center of rotation. 3. The brake drum structure according to claim 1, wherein the stepped portion is formed in a polygonal shape having a plurality of corner portions. 4. The brake drum structure according to claim 1, wherein the stepped portion is formed in a shape having a U-shaped protruding portion.